1. Field of the Invention
This invention relates to an electric cylinder for actuating a door lock which can attach to the existing lock for opening and shutting the door.
2. Description of Related Art
The existing lock for opening and shutting the door is generally designed to use a key so that if the key has been carried and lost or is missing, picking permits the lock to be unlocked by inserting a special tool or a picking tool into the keyhole of the lock. If a lock without a keyhole is attached to the door, additional equipment which has high reparation costs is required.
Recently, a lock structure is proposed to prevent unlawful unlocking without using a proper key, for example, as disclosed in JP-A-2002-276215, however these locks must be provided on the door when it is built, or the door must be reconstructed.